I. Field of the Invention
The present invention relates generally to wheeled stools or dollies that aid mechanics during automotive servicing. More particularly, the present invention relates to portable, wheeled mechanics stools with elevated ladders of the type classified in United States Patent Class 280, Subclasses 32.5 and 32.6, and Class 182, Subclasses 106, 127, 129, 131, 132 and 152.
II. Description of the Prior Art
In the automotive repair arts, it has long been recognized that mechanics or service technicians must have unobstructed access beneath the vehicular chassis or frame. A variety of wheeled "creepers" exist for enabling the serviceman to lie down and slide underneath a vehicle. Whether known as creepers, crawlers, dollies or the like, such well-known support devices also provide a convenient seat that may be readily positioned about the vehicular periphery.
U.S. Pat. No. 2,692,636 shows a combination automobile mechanic's or creeper and stool. The creeper and stool therein disclosed utilizes coil spring members which connect a left and right platform to a center platform. The springs collapse the left and right platforms inwardly to convert the creeper into a stool. Suitable bolts lock the device in the desired position.
It is readily apparent that unobstructed access to the engine compartment of a vehicle undergoing service is highly desirable. Vehicular engine compartments vary greatly in dimensions and volume. Most engine compartments are crowded with numerous complex and hard-to-reach parts that are compactly fitted together. With common utility vehicles (i.e., "SUV's") and small pickup trucks most of the engine compartment is inaccessible without a ladder or some form of stool or lift. Four wheel drive trucks, and other vehicles that have high ground clearance, have engine compartments that are particularly difficult to access and service.
As a result, servicemen often use conventional step ladders or stools that were not originally designed for automotive use. It is not uncommon for the mechanic supported by inappropriate equipment to unsafely bend or reach for obscure parts. His instability may result in a fall or injurious contact with dangerous moving parts, high voltage electricity, or hot radiators or exhaust components. If the engine mechanic positions himself in an unstable disposition, tools or expensive parts will inevitably drop into the engine compartment, possibly contacting the rotating engine fan with significant violence. Worse yet, small fasteners or tools may drop into vital engine compartments if parts such as manifolds, spark plugs, or air cleaners, for example, have been removed. Of course, even minor mishaps like the dropping of tools or, parts upon the ground during service are a common, time-wasting vexation.
Without a support tool or ladder, engine technicians frequently lean over the sides or front of the vehicle. Usually a protective, resilient pad is first placed upon the fenders. Such cushions or mats are not completely effective. Often they do not protect enough of the exposed surface area. Often they have been soiled during their previous use. Even with such precautionary measures, however, the automotive surface has a good chance of being marred, scratched or smeared with oil. Even if the technician is neat and orderly, disadvantages with the latter approach exist. For example, when the mechanic assumes an abnormal position leaning over the fenders to access obscurely positioned parts, muscle strain or other injuries can ensue.
The increasingly numerous intricate parts used in late model motor vehicles merely aggravates the situation. Modem vehicles often require special servicing tools that must be carefully thrust through narrow access crevices or ports before an offending part may be reached. Many critical parts, such as distributors and air conditioning components such as evaporators are inconveniently placed within or adjacent the fire wall, in a position substantially blocked by the engine. Some modem V-8 engines that are transversely mounted within the engine compartment have four of their spark plugs almost completely blocked by the firewall. Thus a system enabling a mechanic to have comfortable and convenient access to the vehicle engine compartment is desirable.
U.S. Pat. No. 4,397,374 discloses structure aimed at providing easier access to the typical engine compartment. Therein disclosed is a support platform for standing or supporting the mechanic in a prone position.
U.S. Pat. No. 2,872,252 discloses an adjustable platform enabling a mechanic stand when adjacent to the motor vehicle. However the device requires frequent adjustments to the horizontal platform to achieve the desired working elevation. Moreover, the disclosed apparatus does not permit the entire mechanic's body to be supported thereon.
U.S. Pat. Nos. 2,970,668 4,072,209 disclose a mechanic's scaffold comprising angularly extended frames. Wheeled carts are known in the prior art. More specifically, U.S. Pat. No. 4,373,761 discloses a combined article mover and worker support. The device, as illustrated, comprises a plurality of stepped horizontal platforms or steps, at least one of which is supported by vertical frame members, while an upstanding handle is usable to support and maintain the balance of a worker standing on the uppermost step.
A number of prior art patent are specifically aimed at reaching the engine compartment from an overhead position. U.S. Pat. No. 4,964,487 discloses a horizontal support platform upon which the mechanic may lie as he pivots into position over the engine compartment. The support is secured to a pivotal frame horizontally extending from an anchored, and immobile, post. With such arrangement a vehicle being serviced must first be properly positioned relative to the work stand. With a mobile cart it is easier to achieve the desired work position, as the vehicle may be approached from any angle, and it may be parked anywhere in the service garage or facility.
U.S. Pat. No. 5,972,955 discloses a wheeled support dolly that comprises a plurality of platforms disposed at different elevations. The device lacks sufficient clearance to position a mechanic directly over a vehicle engine compartment.
U.S. Pat. No. reveals a relatively immobile service platform primarily adapted for servicing large diesel trucks. Although the support platform resembles a wheeled carriage, its major platform segments are fixed. Further, the platform elements do not position the mechanic directly over the engine compartment.
U.S. Pat. Nos. 4,867,273, 4,863,178, 4,397,374 and 4,727,958 illustrate similar mechanics dollies. All show a portable device having a wheeled support frame that may be thrust beneath a vehicle. Certain supports or extensions may be positioned, at least in part, above the engine compartment of a vehicle to be serviced.
U.S. Pat. No. 5,460,392 discloses a dolly having a wheeled, rectangular frame supporting an elevated table. The table is extensible, and it can be positioned over an automobile motor and pivotally adjusted about a radial direction.
U.S. Pat. No. 4,530,419 discloses a wheeled dolly that has an angularly upwardly extending platform support. Because of the orientation of the vertical ladder, it is difficult to squarely position the support platform over an engine compartment.
U.S. Pat. No. 4,542,806 discloses a rigid, wheeled dolly of generally rectangular proportions. Wheeled frame members slide beneath the vehicle being serviced, and an upright vertical stanchion supports a projecting, horizontal platform above the vehicle engine compartment. Means are provide for vertically adjusting the platform. A similar "overhead" support dolly is seen in U.S. Pat. No. 4,618,029.
The fact that a wheeled, mechanic's dolly may provide a support directly above the engine compartment of a vehicle to be serviced is not, in and of itself, enough to remedy the problems n the prior art. An adequate design must be adjustable between a number of configurations that accommodate various vehicles of vastly different dimensions. Besides the requirement of elevational adjustability, a satisfactory dolly must be capable of assuming significantly different angular orientations to minimize the working distance between the user-mechanic and the target engine compartment. Further a satisfactory device must be highly stable, while concurrently allowing the user to safely work vertically (i.e., standing up), horizontally (i.e., lying on top of the support pad), and all configurations between. Further, an ideal machine must allow for angular and elevation adjustments without requiring the user to dismount the unit.